Sorry Makedo626, I thought I was in some kind of a live chat, thanks for responding, I've just posted a much in depth analysis of my problem. No messed pixels, reboot very random but more likely when system is under load directories open, playing videos, no games, but this is not 100 pct can reboot with very little load.
Computer starts very well, computer has been up and running now for 48 hours no reboot but open a video will reboot in minutes. Sitting there quite happily now no reboot so long as I do nothing on the computer. So yes it stays on until I do something. Single normal beep at the start of reboot. Reboots perfectly, most times, a few times seems to get itself lost, press restart and starts fine, a couple of times in the past 4 months I've had serious problems with starting. There seems to be a whole collection of problems here rather than one pattern occurance. No error text before rebooting. Sorry about my original post.
hmm... maybe hard drive problem? or owerheating?.... those are my fast guess. but im not still a guru so if someone else knows better please inform.
i had that kind of problem that computer freezed and restarted after some time of use that time it was hard drive problem. (changed hd now works except these damn usb ports)
second computer had craphic card failure it ran like 48h if i didnt do any hard stuff after starting games or something it showed random pixels and freezed. and also needed to reboot.(changed graphic card and now it works like a charm)
Thank you very much for your time and best effort. I appreciate that. How reliable do you think internal temperature software like speedfan is ? Temperatures show up well within acceptable limits no hotter than 50C Blue (cold/not hot) and Green (safe) symbols showing up on all readings. I'm reluctant to put the computer into the service shop as I live in Thailand and the technical approach out here for virtually any problem is a kind of shotgun approach of new mainboard irrespective of what the situation is. I don't really want to lose a good Asus mainboard for some cheap Chinese replacement unless I'm absolutely certain that is necessary. The same really applies to the HDD would like to make sure first from people on here better in the know than most so called computer technicians we have in Thailand.
Thank you christop. Sounds like a great idea. PSU has been lurking as a possible culprit in the background from articles I have read on the internet from investigating this problem. I've got a house full of computers could you advise on how interchangeable PSU units are between computers how to tell if a PSU from a different computer is compatible with this computer ? Would certainly like to try this one out as soon as I know that I won't damage something else by connecting a non compatible unit. This would be the first time I've done this so just a bit wary.
Just a brief update the video I have been testing this morning which yesterday caused the computer to reboot after 3 and 5 mins has now been running for about 2 hours continuously without any sign of a reboot.